Method of canceling location information request

ABSTRACT

A method of canceling a location information request including receiving a request from a location service client for location information of a target terminal; performing location tracking of the target terminal; and sending a message to the location service client when a privacy profile state has changed. Further, the message indicates that the request from the location service client for location information of the target terminal is canceled.

The present application is a Divisional of co-pending patent applicationSer. No. 13/476,601, filed on May 21, 2012, which is a Continuation ofpatent application Ser. No. 11/293,259, filed on Dec. 5, 2005, now U.S.Pat. No. 8,190,169, issued on May 29, 2012, which claims prioritybenefit of Korean Patent Application No. 10-2004-102005 filed on Dec. 6,2004 in Korea, the entire contents of which are incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of canceling a locationinformation request, and more particularly, to a method of canceling alocation information request according to privacy information of aterminal whose location is to be tracked.

2. Description of the Related Art

In general, a mobile communication system provides a location servicefor delivering the location of a terminal (e.g., mobile station) to aspecific entity periodically or according to a request by having afunctional portion for calculating the location of a terminal in amobile communication network.

Methods of calculating the location of the terminal include a cell-IDmethod of delivering the ID of a cell of the terminal, a method ofcalculating the location of the terminal by a triangular surveyprocedure after measuring the time it takes a signal wave to reach eachneighbor base station from the terminal, a method utilizing a GPS(global positioning system) and so on.

In a related art location service, when a specific Location ServiceClient (hereinafter, a LCS client) periodically or immediately requestsfor a location information of a terminal, a location server calculates alocation value by tracking the location of the terminal and thenforwards it to the LCS client. At this point, the LCS client havingrequested for the location information may cancel the locationinformation request.

However, in the event that it is impossible to track the location of theterminal whose location tracking is requested by the LCS client, thelocation server cannot cancel the location tracking request of the LCSclient and also cannot provide location information of the terminal tothe LCS client. Therefore, as the LCS client cannot know that thelocation server is unable to perform location tracking, it can continueto request for location information of the terminal if it is notprovided with location information from the location server.

As seen from above, in the related art location service, although theLCS client having requested for location information of a specificterminal may cancel the request, nothing has been defined with respectto a method in which the location server having received a locationtracking request from the LCS client that later cancels the locationtracking request.

Consequently, in the case that the location server is unable to trackthe location of a terminal requested by the LCS client, there is aproblem that a communication network is used inefficiently and the loadof the location server increases since the LCS client continues torequest the location server for location information of the terminal.

BRIEF DESCRIPTION OF THE INVENTION

Therefore, an object of the present invention is to provide a method ofcanceling a location information request in which a location server cancancel a location information request forwarded from a LCS client byitself.

Another object of the present invention is to provide a method ofcanceling a location information request in which a location server cancancel a location information request by itself according to an updateof privacy information of a terminal whose location information isrequested by a LCS client.

To accomplish the above objects, there is provided a method of cancelinga location information request according to the present invention,wherein in a case where a location server receives a locationinformation request about a specific terminal but the location servercannot provide location information of the terminal, the location serverinitiates to cancel the location information request.

A method of canceling a location information request according to thepresent invention comprises the steps of: an external client requestinga location server for information of a specific terminal; the locationserver checking privacy information of the terminal; and the locationserver canceling the location information request according to theprivacy information of the terminal.

A method of canceling a location information request according to thepresent invention comprises the steps of: a location server receiving alocation information request message about a specific terminal; if theterminal belongs to a service area of the location server, the locationserver calculating the location of the terminal and checking privacyinformation of the terminal; and if the privacy of the terminal is‘non-disclosed’ state, the location server forwarding a locationinformation request cancellation message.

A method of canceling a location information request according to thepresent invention comprises the steps of: a first location serverreceiving a location information request message about a specificterminal; if the terminal belongs to a service area of a second locationserver, the first location server forwarding a location informationrequest message about the terminal to the second location server; and ifthe privacy of the terminal is ‘non-disclosed’ state, the first locationserver forwarding a location information request cancellation message.

A method of canceling a location information request according to thepresent invention, in the case of forwarding location information of aterminal belonging to a service area of a location server, comprisingthe steps of: the location server receiving a Standard LocationImmediate Request message requesting for location information of theterminal; the location server calculating the location of the terminaland checking privacy information of the terminal; and if the privacy ofthe terminal is ‘non-disclosed’ state, the location server optionallyforwarding a Standard Location Immediate Report message or a StandardLocation Immediate Stop Answer message.

A method of canceling a location information request according to thepresent invention, in the case of forwarding location information of aterminal belonging to a service area of a location server, comprisingthe steps of: the location server receiving a Triggered LocationReporting Request message requesting for location information of theterminal; if the condition set up for the Triggered Location ReportingRequest message is satisfied, the location server calculating thelocation of the terminal and checking privacy information of theterminal; if the privacy of the terminal is ‘non-disclosed’ state, thelocation server optionally forwarding a Triggered Location Reportmessage or a Triggered Location Reporting Stop Answer message.

A method of canceling a location information request according to thepresent invention, in the case that a first server forwards locationinformation of a terminal belonging to a service area of a secondlocation server, comprising the steps of: the first location serverreceiving a Standard Location Immediate Request message requesting forlocation information of the terminal; the first location serverforwarding a location information request message about the terminal tothe second location server and receiving a location information reportmessage containing the location information of the terminal; the firstlocation server checking privacy information of the terminal; and if theprivacy of the terminal is ‘non-disclosed’ state, optionally forwardinga Standard Location Immediate Report message or a Standard LocationImmediate Stop Answer message.

A method of canceling a location information request according to thepresent invention, in the case that a first server forwards locationinformation of a terminal belonging to a service area of a secondlocation server, comprising the steps of: the first location serverreceiving a Triggered Location Reporting Request message requesting forlocation information of the terminal; the first location serverforwarding a location information request message about the terminal tothe second location server and receiving a location information reportmessage containing the location information of the terminal; the firstlocation server checking privacy information of the terminal; and if theprivacy of the terminal is ‘non-disclosed’ state, optionally forwardinga Triggered Location Report message or a Triggered Location ReportingStop Answer message.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

In the drawings:

FIG. 1 illustrates the configuration of an exemplary location serviceprovision system according to the present invention;

FIG. 2 illustrates an exemplary method of canceling a locationinformation request between a LCS client and an exemplary locationserver according to the present invention;

FIG. 3 illustrates an exemplary method of canceling a locationinformation request between location servers according to the presentinvention;

FIG. 4 illustrates an exemplary location service method according to thepresent invention;

FIG. 5 illustrates an exemplary method of canceling a locationinformation request according to a first embodiment of the presentinvention;

FIG. 6 illustrates an exemplary method of canceling a locationinformation request according to a second embodiment of the presentinvention;

FIG. 7 illustrates an exemplary method of canceling a locationinformation request according to a third embodiment of the presentinvention;

FIG. 8 illustrates an exemplary method of canceling a locationinformation request according to a fourth embodiment of the presentinvention; and

FIG. 9 illustrates an exemplary location information requestcancellation message implemented by XML according to the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, preferred embodiments of a method of canceling a locationinformation request according to the present invention will be describedwith reference to the accompanying drawings.

The present invention relates to a method of canceling a locationinformation request in which, in the case that a location server havingreceived a location information request about a specific terminal (e.g.,mobile station, handset, wireless communication device, etc.) from aLocation Service Client (LCS) client is unable to track the location ofthe terminal, the location server forwards a location informationrequest cancellation message to the LCS client. At this point, thelocation information request cancellation message forwarded to the LCSclient by the location server is a Triggered Location Report message orTriggered Location Reporting Stop Answer message and a Standard LocationImmediate Report message or Standard Location Immediate Stop Answermessage that are defined in the MLP (Mobile Location Protocol).

If the location server has received a Standard Location Report Requestmessage from the LCS client, it forwards a Standard Location Reportmessage. If the location server has received a Triggered Location ReportRequest message from the LCS client, it forwards a Triggered LocationReport message or a Triggered Location Reporting message.

In a case where the Triggered Location Report message, TriggeredLocation Reporting Stop Answer message and Standard Location Reportmessage are used as the location information request cancellationmessage, the parameter indicating the reason why the locationinformation request is canceled may be added into the message.

FIG. 1 illustrates an exemplary configuration of a location serviceprovision system according to the present invention. The locationservice provision system may be divided into a first service area 100 inwhich a home location server 130 tracks the location of a terminal 150and a second service area 200 in which a visiting location server 230tracks the location of the terminal 150.

The first service area 100 may include a LCS client 110 for requestinglocation information of a terminal 150 whose location is to be tracked,a home location server 130 for providing location information of theterminal 150 to the LCS client 110, a request location server 120serving as a proxy between the LCS client 100 and the home locationserver 130, and a privacy check entity (PCE) 140 storing privacyinformation about the terminal 150. The second service area 200 includesa visiting location server 230 for tracking the location of the terminal150 and forwarding acquired location information to the home locationserver 130 if the terminal 150 belongs to the second service area.

If the terminal 150 belongs to the first service area, when the homelocation server 130 receives a location information request message fromthe LCS client 110, the home location server 130 forwards a locationinformation report message or a location information requestcancellation message to the LCS client 110 according to privacyinformation of the terminal 150 stored in the privacy check server 140.Here, the privacy information is information informing whether thelocation information of the terminal 150 is ‘disclosed’ or‘non-disclosed’ state, which is stored in the privacy check server 140by the terminal 150 or other interworking device.

On the other hand, if the terminal 150 belongs to the second servicearea, the home location server 130 cannot detect the location of theterminal 150 by itself, and thus forwards a location information requestmessage to the visiting location server 230. The visiting locationserver 230 forwards a location information report message containing thelocation information of the terminal 150 to the home location server130, and the home location server 130 checks the privacy information ofthe terminal 150 from the privacy check server 140. When the homelocation server 130 confirms through the privacy information that thelocation information of the terminal 150 is ‘non-disclosed’ state, itforwards a location information request cancellation message to the LCSclient 110 and the visiting location server 230.

At this point, the location information request message, locationinformation report message and location information request cancellationmessage forwarded between the LCS client and the requesting server is aMobile Location Protocol (hereinafter referred to as MLP), while thelocation information request message, the location information reportmessage, and the location information request cancellation messageforwarded between the requesting server and the home location server andbetween the home location server and the visiting location server is aRoaming Location Protocol (hereinafter referred to as RLP). The MLP isan application protocol between an external LCS client and a locationserver, and the RLP is an application protocol between location servers.

FIG. 2 illustrates an exemplary method of canceling a locationinformation request between a LCS client and a location server accordingto the present invention, in which a MLP is used as a message forwardedbetween the LCS client and the location server. Referring to FIG. 2, theLCS client forwards a Triggered Location Reporting Request message tothe location server in order to request the location information of aspecific terminal, and the location server forwards a Triggered LocationReporting Answer message as a response message. Thereafter, the locationserver tracks the location of the terminal at a time interval set up forthe Triggered Location Reporting Request message or when a specificpreset event occurs, and delivers a Triggered Location Report messagecontaining resulting acquired location information to the LCS client.

If the location server unilaterally decides to terminate the locationreporting, the stop reporting information shall be carried (included) inthe Triggered Location Report message. The cancellation of the TriggeredLocation Reporting Request message could be initiated by the locationserver itself for certain reasons, such as privacy profile updating. Inthis case, the Triggered Location Reporting Stop Answer message may besent without a preceding Triggered Location Reporting Stop Requestmessage.

Parts of the Triggered Location Reporting Stop Answer (TLRSA) messagemay be implemented by XML as follows:

<!ENTITY % extension.param “”> <!ELEMENT tlrsa  ((req_id| (result, addinfo?)) %extension.param;)> <!ATTLIST tlrsa       ver CDATA  #FIXED“3.0.0”>

The Triggered Location Reporting Stop Answer message contains the resultinformation of location tracking performed by the location server. Theresult information is provided through a “Result Code” indicating atleast one of a result, a location value and an individual positioningfor a request from the LCS client.

FIG. 3 illustrates an exemplary method of canceling a locationinformation request between location servers according to the presentinvention. Messages as illustrated therein are forwarded by using a RLP.Referring to FIG. 3, a location server A forwards a Triggered RoamingLocation Reporting Request message to a location server B in order torequest the location information of a terminal belonging to the area ofthe location server B, and the location server B forwards a TriggeredRoaming Location Reporting Answer message as a response message.Thereafter, the location server B tracks the location of the terminal ata time interval set up for the Triggered Roaming Location ReportingRequest message and when a specific set event occurs, and delivers aTriggered Roaming Location Report message containing resulting acquiredlocation information to the location server A.

Thereafter, when the location server A forwards a Triggered RoamingLocation Reporting Stop Request message to the location server B, thelocation server B stops a location tracking procedure and forwards aTriggered Roaming Location Reporting Stop Answer message to the locationserver A. At this time, the location server B stops the locationtracking procedure by itself and may forward a Triggered RoamingLocation Reporting Stop Answer message to the location server A eventhough it has not received a Triggered Roaming Location Reporting StopRequest message. Namely, the cancellation of the Triggered RoamingLocation Reporting Request message may be initiated by any of thelocation servers for certain reasons, such as an updating of privacyinformation.

Parts of the Triggered Roaming Location Report Stop Answer (TLRSA)message may be implemented by XML as follows:

<!ENTITY % extension.param “”> <!ELEMENT trlrsa ((req_id| (result,add_info?)) %extension.param;)> <!ATTLIST trlrsa  ver CDATA  #FIXED“1.0.0”>

The result information contained in the Triggered Location ReportingStop Answer message may be configured with reference to a “Result Code”defined in the MLP.

FIG. 4 illustrates an exemplary location service method according to thepresent invention. Referring to the drawing, a service procedureperformed in a home location server will be described.

When the home location server receives from a LCS client a locationinformation request message about a terminal whose location is to betracked (S10), the home location server checks the privacy informationof the terminal (S11). The privacy information indicates if the locationinformation of the terminal is ‘disclosed’, and it may be set up in aprivacy check entity by the terminal or other external interworkingdevice.

If the privacy information of the terminal is set to the ‘disclosed’state, the LCS client investigates the service area where the terminalbelongs through a HLR (home location register) (S12). If the terminalexists in a home service area, the home location server calculates alocation value of the terminal (S16), and then it checks the privacyinformation of the terminal once again (S17). If the privacy informationis set to the ‘non-disclosed’ state by update, the home location serverforwards a location information request cancellation message aboutterminal to LCS client (S18). However, If the privacy information of theterminal is still set to the ‘disclosed’ state, the home location serverforwards a location information report message about the terminal to theLCS client (S19). The location information report message contains alocation value of the terminal calculated by the home location server.

On the other hand, if the terminal does not exist in a home servicearea, the home location server forwards a location information requestmessage to the location server (i.e., visiting location server) of thearea where the terminal belongs (S13). Then, the visiting locationserver calculates a location value of the terminal (S14) and it sendsthe location information report message about the terminal to the homelocation sever (S15). The home location server upon receiving thelocation information report message checks whether the privacyinformation is updated (S17). If the privacy information is set to the‘non-disclosed’ state by update, the home location server forwardslocation information request cancellation message about terminal to LCSclient (S18), and If the privacy information of the terminal is notupdated, the home location server forwards a location information reportmessage about the terminal to the LCS client (S19).

However, in steps S12 and S16, if the privacy information of theterminal checked by the home location server is set to the‘non-disclosed’ state, the home location server forwards a locationinformation request cancellation message about the terminal to the LCSclient S17. The location information request cancellation messagecontains information indicating that the privacy of the terminal is‘non-disclosed’ state.

The aforementioned method of canceling a location information requestcan be carried out by using a Standard Location Immediate service and aTriggered Location Reporting service among a variety of locationservices defined in the MLP. The Standard Location Immediate service isa service used when a response to a location information request fromthe LCS client is immediately required, and the Triggered LocationReporting service is a service for providing location information of amobile service subscriber at a predetermined time interval or when aspecific event occurs.

FIG. 5 illustrates an exemplary method of canceling a locationinformation request according to a first embodiment of the presentinvention. A method of canceling a location information request will bedescribed with respect to the case that a terminal whose location is tobe tracked belongs to the area of a home location server. In the firstembodiment, a Standard Location Immediate Service is utilized.

A LCS client 110 forwards a location information request message to ahome location server 130 through a requesting location server 120 inorder to request for location information of a specific terminal (S21).In the Standard Location Immediate service, the location informationrequest message is a Standard Location Immediate Request message.

The location sever 130 having received the Standard Location ImmediateRequest message forwards a Standard Location Immediate Answer message asa response message to the above message to the LCS client 110 throughthe requesting location server 120 (S22).

The home location server 130 forwards a Location Privacy AssertionRequest message to a privacy check entity 140 in order to requestprivacy information of the terminal whose location is to be tracked(S23). The privacy check entity 140 stores the privacy informationindicating whether the location information of the terminal is‘disclosed’ or ‘non-disclosed’ state by the terminal or otherinterworking device.

The privacy check entity 140 forwards a Location Privacy AssertionResponse message containing the privacy information of the terminal tothe home location server 130 (S24). At this time, the home locationserver 130 checks the privacy information contained in the LocationPrivacy Assertion Response message, and if the privacy of the terminalis ‘disclosed’, it calculates a location value of the terminal (S25).And, the home location server 130 re-checks the privacy information ofthe terminal set up in the privacy check entity 140 in the same manneras in steps S23 and S24 (S26 and S27). Here, the Location PrivacyAssertion Request message and the Location privacy Assertion Responsemessage are forwarded by using a privacy check protocol (PCP).

At this time, if the privacy of the terminal 150 is changed from‘disclosed’ to ‘non-disclosed’ state and thus the location server 130 isunable to forward the location information, the location server 130forwards a location information request cancellation message to the LCSclient 110 (S28). Here, the location server can optionally forward aStandard Location Immediate Report message or a Standard LocationImmediate Stop Answer message as the location information requestcancellation message.

The Standard Location Immediate Report message and the Standard LocationImmediate Stop Answer message contain a parameter specifying the reasonwhy the home location server cancels the location information request.The home location server can cancel the location information requestfrom the LCS client by using a dedicated message indicating that thelocation information request is canceled, instead of using a messagecontaining a parameter.

In FIG. 5, the procedure after step S25 has been illustrated under theassumption that the privacy of the terminal is disclosed in the LocationPrivacy Assertion Response message in step S24. However, if the privacyof the terminal is ‘non-disclosed’ state, step S28 is carried outwithout undergoing steps S25 to S27.

FIG. 6 illustrates an exemplary method of canceling a locationinformation request according to a second embodiment of the presentinvention, in which a method of canceling a location information requestin a case where a terminal whose location is to be tracked belongs tonot the area of the home location server but to the area of anotherlocation server (i.e., visiting location server). The second embodimentutilizes a Standard Location Immediate service.

A LCS client 110 forwards a Standard Location Immediate Request messageto a home location server 130 through a requesting location server 120in order to request the location information of a specific terminal(S31). The location sever 130 having received the Standard LocationImmediate Request message forwards a Standard Location Immediate Answermessage as a response message to the above message to the LCS client 110(S32).

The home location server 130 forwards a Location Privacy AssertionRequest message to a privacy check entity 140 in order to request forprivacy information of the terminal whose location is to be tracked(S33), and receives a Location Privacy Assertion Response messagecontaining the privacy information of the terminal (S34). The privacyinformation is information set up in the privacy check entity 140 by theterminal or other interworking device, which indicates whether thelocation information of the terminal is ‘disclosed’ or ‘non-disclosed’state. Here, the location server can optionally forward a StandardLocation Immediate Report message or a Standard Location Immediate StopAnswer message as the location information request cancellation message.

When the home location server 130 having received the Location PrivacyAssertion Response message confirms through the privacy informationcontained in the message that the location information of the terminalis disclosed, the home location server 130 checks the location of theterminal. Since the terminal does not belong to the home service area,the home location server 130 forwards a Standard Roaming LocationImmediate Request message for requesting the location information of theterminal to a location server 230 of the service area where the terminalbelongs (S35). The visiting location server 230 delivers a responsemessage (i.e., Standard Roaming Location Immediate Answer) to theStandard Roaming Location Immediate Request message to the home locationserver 130, and calculates the location value of the terminal (S37).And, the visiting location server 230 allows the location value of theterminal to be contained in the Standard Roaming Location ImmediateReport message to forward it to the home location server 130 (S38).

Prior to forwarding the location information to the LCS client 110, thehome location server 130 having acquired the location information of theterminal re-checks the privacy information of the terminal set up in theprivacy check entity 140 (S38 to S40).

At this time, in the case that the privacy information of the terminalis changed and thus the location server 130 is unable to forward thelocation information, the location server 130 forwards a locationinformation request cancellation message to the LCS client 110 throughthe requesting location server 120 (S41). Here, the location server canoptionally forward a Standard Location Immediate Report message or aStandard Location Immediate Stop Answer message as the locationinformation request cancellation message.

The Standard Location Immediate Report message and the Standard LocationImmediate Stop Answer message contain a parameter specifying the reasonwhy the home location server cancels the location information request.The home location server can cancel the location information requestfrom the LCS client by using a dedicated message indicating that thelocation information request is canceled, instead of using a messagecontaining a parameter.

FIG. 7 illustrates an exemplary method of canceling a locationinformation request according to a third embodiment of the presentinvention, in which a method of canceling a location information requestin a case where a terminal whose location is to be tracked belongs tothe area of the home location server. The third embodiment utilizes aTriggered Location Reporting service.

A LCS client 110 forwards a location information request message to ahome location server 130 through a requesting location server 120 inorder to request for location information of a specific terminal (S51).At this time, the location information request message is a TriggeredLocation Reporting Request message, which is a message forwarded torequest the home location server 130 to track the location of theterminal at a time interval set up for the message or when a specificevent occurs.

The location sever 130 having received the Triggered Location ReportingRequest message forwards a Triggered Location Reporting Answer messageas a response message to the LCS client 110 (S52), and forwards aLocation Privacy Assertion Request message requesting for privacyinformation of the terminal to a privacy check entity 140 (S53). Theprivacy check entity 140 stores the privacy information of the terminalset up by the terminal or other interworking device, and the privacyinformation indicates whether the location information of the terminalis ‘disclosed’ or ‘non-disclosed’ state

The privacy check entity 140 having received the Location PrivacyAssertion Request message allows the privacy information of the terminalto be contained in the Location Privacy Assertion Response message andforwards it to the home location server 130. At this time, the LocationPrivacy Assertion Request message and the Location Privacy AssertionResponse message are forwarded by using a privacy check protocol (PCP).

If the location server 130 confirms that the privacy of the terminal is‘non-disclosed’ state, it forwards a location information requestcancellation message to the LCS client 110. At this time, the locationinformation request cancellation message may be a Triggered LocationReport message or a Triggered Location Reporting Stop Answer message.

On the other hand, if the location server 130 confirms that the privacyof the terminal is ‘disclosed’, it tracks the location of the terminalat a time interval set up for the Triggered Location Reporting Requestmessage or when an event occurs and calculates a location value (S55).And, the home location server 130 checks through the privacy checkentity 140 if the privacy information of the terminal 150 is updated(S56 and S57).

If the privacy of the terminal is updated from ‘disclosed’ to‘non-disclosed’ state, the home location server 130 forwards a TriggeredLocation Report message or a Triggered Location Reporting Stop Answermessage to the LCS client 110 (S58). The Triggered Location Reportmessage and the Triggered Location Reporting Stop Answer message containa parameter indicating the reason why the location information requestis canceled. The location server can cancel the location informationrequest from the LCS client by using a dedicated message indicating thatthe location information request is canceled, instead of using a messagecontaining a parameter.

Meanwhile, the location server 130 having forwarded the TriggeredLocation Report message or Triggered Location Reporting Stop Answermessage may cancel location tracking settings for the terminal that arestored therein.

FIG. 8 illustrates an exemplary method of canceling a locationinformation request according to a fourth embodiment of the presentinvention, in which a method of canceling a location information requestin a case where a terminal whose location is to be tracked belongs notto the area of the home location server but to the area of otherlocation server (visiting location server). The fourth embodimentutilizes a Triggered Location Reporting service.

A LCS client 110 forwards a Triggered Location Reporting Request messageto a home location server 130 through a requesting location server 120in order to request for location information of a specific terminal(S61). The location sever 130 having received the Triggered LocationReporting Request message forwards a Triggered Location Reporting Answermessage as a response message to the above message to the LCS client 110(S62), and requests for privacy information of the terminal whoselocation is to be tracked by forwarding a Location Privacy AssertionRequest message to a privacy check entity 140 (S63). The privacy checkentity 140 stores the privacy information of the terminal set up by theterminal or other interworking device, and the privacy informationindicates whether the location information of the terminal is‘disclosed’ or ‘non-disclosed’ state.

The privacy check entity 140 having received the Location PrivacyAssertion Request message allows the privacy information of the terminalto be contained in the Location Privacy Assertion Response message andforwards it to the home location server 130 (S64). At this time, theLocation Privacy Assertion Request message and the Location PrivacyAssertion Response message are forwarded by using a privacy checkprotocol (PCP).

Once the home location server 130 confirms that the privacy of theterminal is ‘disclosed’, it forwards a Triggered Roaming LocationReporting Request message to a location server 230 of the service areato which the terminal is moved (S65), and the visiting location server230 forwards a Triggered Roaming Location Reporting Answer message as aresponse message (S66).

The visiting location server 230 tracks the location of the terminal ata time interval set up for the Triggered Roaming Location ReportingRequest message or when an event occurs and calculates a location value(S67). And, the visiting location server 130 forwards a TriggeredRoaming Location Report message containing the location value of theterminal to the home location server 130 (S68). At this time, theTriggered Roaming Location Reporting Request message, Triggered RoamingLocation Reporting Answer message and Triggered Roaming Location Reportmessage sent and received between the home location server 130 and thevisiting location server 230 are forwarded according to a RLP.

The home location server 130 detects the location of the terminalthrough the Triggered Roaming Location Report message, and then checksthrough the privacy check entity 140 if the privacy information of theterminal is updated (S69 and S70).

If the privacy information of the terminal is updated, and thus the homelocation server 130 cannot forward the location information of theterminal, it forwards a Triggered Location Report message or a TriggeredLocation Reporting Stop Answer message to the LCS client 110 (S71). TheTriggered Location Report message and the Triggered Location ReportingStop Answer message contain a parameter indicating the reason why thelocation information request is canceled. The location server can cancelthe location information request from the LCS client by using adedicated message indicating that the location information request iscanceled, instead of using a message containing a parameter. Meanwhile,the location server 130 may cancel a location tracking request for theterminal by forwarding a Cancellation Request message to the visitinglocation server 230 (S72). That is, the home location server 130 mayforward the Cancellation Request message before, simultaneously with orafter forwarding the location information request message to the LCSclient 110.

As described above, in the Triggered Location Reporting service, thelocation information request cancellation message forwarded by thelocation server in order to cancel the location information request ofthe LCS client is the Triggered Location Report message or TriggeredLocation Reporting Stop Answer message. At this time, the locationserver may forward the Triggered Location Reporting Stop Answer messageto the LCS client even when it has not received the Triggered LocationReporting Stop Answer message.

FIG. 9 illustrates an exemplary location information requestcancellation message implemented by XML according to the presentinvention. As illustrated therein, the location information requestcancellation message may contain a parameter of ‘CANCELLATION OFTRIGGERED LOCATION REQUEST’ or ‘PRIVACY PROFILE CHANGED’. For example,in a case where the privacy information of the terminal whose locationis to be tracked is updated and thus the location server cannot providelocation information, a corresponding parameter ‘PRIVACY PROFILECHANGED’ is contained in the location information request cancellationmessage along with a corresponding result code (Resid=116).Alternatively, in a case where the location server cancels the locationinformation request by itself, a parameter ‘CANCELLATION OF TRIGGEREDLOCATION REQUEST’ indicating that the requested triggered locationreport is cancelled is contained in the location information requestcancellation message along with a corresponding result code (Resid=114).

The following table defines exemplary parts of the result codes thatindicate the result of the request or individual positioning. The errorcodes for the request specific errors may range from 100 to 199.

Resid Slogan Description 110 INVALID PROTOCOL A protocol element in therequest ELEMENT VALUE has an invalid value. The element is indicated inADD_INFO. 111 INVALID PROTOCOL A protocol element attribute in theELEMENT ATTRIBUTE request has a wrong value. The ele- VALUE ment isindicated in ADD_INFO. 112 PROTOCOL ELEMENT A specific value of aprotocol VALUE NOT element is not supported in the SUPPORTED LocationServer. The element and value are indicated in ADD_INFO. 113 PROTOCOLELEMENT A specific value of a protocol ele- ATTRIBUTE VALUE mentattribute is not supported in the NOT SUPPORTED Location Server. Theattribute and value are indicated in ADD_INFO. 114 CANCELLATION OF Therequested triggered location TRIGGERED LOCATION report is cancelled.REQUEST

In the first and second embodiments, the result codes and parameters arecontained in the Standard Location Immediate Report message or StandardLocation Immediate Stop Answer message. In the third and fourthembodiments, they are contained in the Triggered Location Report messageor Triggered Location Stop Answer message.

As seen from above, in the method of canceling a location informationrequest according to the present invention, if the location servercannot forward location information of a terminal requested from the LCSclient, the location server can cancel the location information requestby itself.

Moreover, in the method of canceling a location information requestaccording to the present invention, in the case that the location servercannot forward location information of the terminal due to an update ofthe privacy information of the terminal requested from the LCS client,the privacy for location tracking can be incorporated in real time bythe location server forwarding a location information requestcancellation message to the LCS client. Further, in the case that thelocation server is unable to forward location information of theterminal requested from the LCS client, it is possible to prevent theLCS client from generating a location information request again bycanceling the request from the LCS client.

The present invention provides the location sever performing a method ofcanceling a location information request. The location sever comprises atransceiver module, a privacy check module and a processor. Thetransceiver module may receive a location information request about aspecific terminal to be tracked from an external client. The receivedlocation information request is canceled if the privacy information ofthe terminal is being updated. Also, the transceiver module maytransmit, to the external client, a location information requestcancellation to cancel the received location information request. Here,the location information request cancellation includes a parameterspecifying the reason why the location information request is beingcanceled. The privacy check module checks privacy information of theterminal set up in a privacy check entity upon receiving the locationinformation request. The processor cooperates with the transceivermodule and the privacy check module to cancel the received locationinformation request according to the checked privacy information.

Here, if the terminal belongs to a service area of the location server,the processor calculates the location of the terminal, and if theprivacy information of the terminal is not permitted to be disclosed,the transceiver module sends the location information requestcancellation without the external client's location reporting stoprequest. If the location information request is a Standard LocationImmediate Request message, and if the privacy information of theterminal is not permitted to be disclosed, the processor and thetransceiver cooperate to selectively send a Standard Location ImmediateReport message or a Standard Location Immediate Stop Answer messagewithout a preceding Standard Location Immediate Stop Request message. Ifthe location information request is a Triggered Location ReportingRequest message, and if a condition for the Triggered Location ReportingRequest message is satisfied, then the location of the terminal iscalculated and the privacy information is checked, and if the privacyinformation of the terminal is not permitted to be disclosed, theprocessor and transceiver cooperate to selectively send a TriggeredLocation Report message or a Triggered Location Reporting Stop Answermessage without a preceding Triggered Location Reporting Stop Requestmessage.

On the other hand, if the terminal belongs to a service area of adifferent location server, the location server forwards the locationinformation request to the different location server, and if the privacyinformation of the terminal is not permitted to be disclosed, thetransceiver module sends the location information request cancellationwithout the external client's location reporting stop request. If thelocation information request is a Standard Location Immediate Requestmessage, a location information request message about the terminal issent to the different location server and a location information reportmessage containing the location information of the terminal is receivedfrom the different location server; and if the privacy information ofthe terminal is not permitted to be disclosed, the processor and thetransceiver cooperate to selectively send a Standard Location ImmediateReport message or a Standard Location Immediate Stop Answer messagewithout a preceding Standard Location Immediate Stop Request message. Ifthe location information request is a Triggered Location ReportingRequest message, a location information request message about theterminal is sent to the different location server and a locationinformation report message containing the location information of theterminal is received from the different location server, and if theprivacy information of the terminal is not permitted to be disclosed,the processor and transceiver cooperate to selectively send a TriggeredLocation Report message or a Triggered Location Reporting Stop Answermessage without a preceding Triggered Location Reporting Stop Requestmessage.

The foregoing embodiments and advantages are merely exemplary and arenot to be construed as limiting the present invention. The presentteaching can be readily applied to other types of apparatuses. Thedescription of the present invention is intended to be illustrative, andnot to limit the scope of the claims. Many alternatives, modifications,and variations will be apparent to those skilled in the art. In theclaims, means-plus-function clauses are intended to cover the structuredescribed herein as performing the recited function and not onlystructural equivalents but also equivalent structures.

What is claimed is:
 1. A method of canceling a location informationrequest, comprising: receiving, by a first location server using aroaming location protocol (RLP), a triggered location reporting requestmessage from a second location server for location reporting of aterminal to be tracked; deciding, by the first location server, tocancel the location reporting; and sending, from the first locationserver using the RLP to the second location server, which sent thetriggered location reporting request message, a triggered locationreporting stop answer message if the location reporting is decided to becanceled, wherein the triggered location reporting stop answer messageindicates that the location reporting is canceled, wherein the locationreporting is canceled due to a change in privacy profile, and whereinthe triggered location reporting stop answer message is sent withoutreceiving a preceding triggered location reporting stop request message.2. The method of claim 1, wherein the change in privacy profile isindicated by a privacy check entity.
 3. The method of claim 1, furthercomprising: sending, from the first location server using the RLP to thesecond location server, a triggered location reporting answer message inresponse to the triggered location reporting request message.